Search Results for author: Andreas F. Molisch

Found 31 papers, 5 papers with code

Resource-Aware Hierarchical Federated Learning in Wireless Video Caching Networks

no code implementations6 Feb 2024 Md Ferdous Pervej, Andreas F. Molisch

Based on this bound, we minimize a weighted utility function for jointly configuring the controllable parameters to train the RawHFL energy efficiently under practical resource constraints.

Federated Learning

A Scalable and Generalizable Pathloss Map Prediction

1 code implementation6 Dec 2023 Ju-Hyung Lee, Andreas F. Molisch

Large-scale channel prediction, i. e., estimation of the pathloss from geographical/morphological/building maps, is an essential component of wireless network planning.

Transfer Learning

Handover Protocol Learning for LEO Satellite Networks: Access Delay and Collision Minimization

no code implementations31 Oct 2023 Ju-Hyung Lee, Chanyoung Park, Soohyun Park, Andreas F. Molisch

This study presents a novel deep reinforcement learning (DRL)-based handover (HO) protocol, called DHO, specifically designed to address the persistent challenge of long propagation delays in low-Earth orbit (LEO) satellite networks' HO procedures.

Stochastic Geometry Analysis of a New GSCM with Dual Visibility Regions

no code implementations18 Aug 2023 Anish Pradhan, Harpreet S. Dhillon, Fredrik Tufvesson, Andreas F. Molisch

For example, the condition of visibility of a scatterer from the perspective of a BS is different from that of an MS and depends on the height of the scatterer.

Point Processes

Novel LoS $β-γ$ THz Channel Unifying Molecular Re-radiation Manifestations

no code implementations18 Aug 2023 Anish Pradhan, J. Kartheek Devineni, Andreas F. Molisch, Harpreet S. Dhillon

This paper introduces a novel line-of-sight (LoS) $\beta-\gamma$ terahertz (THz) channel model that closely mirrors physical reality by considering radiation trapping.

Simple and Effective Augmentation Methods for CSI Based Indoor Localization

no code implementations19 Nov 2022 Omer Gokalp Serbetci, Ju-Hyung Lee, Daoud Burghal, Andreas F. Molisch

We also showed that if we further augment the dataset with the proposed techniques, test accuracy is improved more than three-fold.

Data Augmentation Indoor Localization

Robust Optimization of RIS in Terahertz under Extreme Molecular Re-radiation Manifestations

no code implementations2 Oct 2022 Anish Pradhan, Mohamed A. Abd-Elmagid, Harpreet S. Dhillon, Andreas F. Molisch

Terahertz (THz) communication signals are susceptible to severe degradation because of the molecular interaction with the atmosphere in the form of subsequent absorption and re-radiation.

THz Band Channel Measurements and Statistical Modeling for Urban Microcellular Environments

no code implementations3 Dec 2021 Naveed A. Abbasi, Jorge Gomez-Ponce, Revanth Kondaveti, Ashish Kumar, Eshan Bhagat, Rakesh N S Rao, Shadi Abu-Surra, Gary Xu, Charlie Zhang, Andreas F. Molisch

The THz band (0. 1-10 THz) has attracted considerable attention for next-generation wireless communications, due to the large amount of available bandwidth that may be key to meet the rapidly increasing data rate requirements.

Artificial intelligence enabled radio propagation for communications-Part II: Scenario identification and channel modeling

no code implementations24 Nov 2021 Chen Huang, Ruisi He, Bo Ai, Andreas F. Molisch, Buon Kiong Lau, Katsuyuki Haneda, Bo Liu, Cheng-Xiang Wang, Mi Yang, Claude Oestges, Zhangdui Zhong

This two-part paper investigates the application of artificial intelligence (AI) and in particular machine learning (ML) to the study of wireless propagation channels.

Artificial intelligence enabled radio propagation for communications-Part I: Channel characterization and antenna-channel optimization

no code implementations24 Nov 2021 Chen Huang, Ruisi He, Bo Ai, Andreas F. Molisch, Buon Kiong Lau, Katsuyuki Haneda, Bo Liu, Cheng-Xiang Wang, Mi Yang, Claude Oestges, Zhangdui Zhong

To provide higher data rates, as well as better coverage, cost efficiency, security, adaptability, and scalability, the 5G and beyond 5G networks are developed with various artificial intelligence techniques.

A Geometry-Based Stochastic Model for Truck Communication Channels in Freeway Scenarios

no code implementations20 Oct 2021 Chen Huang, Rui Wang, Cheng-Xiang Wang, Pan Tang, Andreas F. Molisch

We validate this model by contrasting the root-mean-square delay spread and the angular spreads of departure/arrival derived from the channel model with the outcomes directly derived from the measurements.

Collision Avoidance

Evaluation on Energy Efficiency of UE in UL Cell-Free Massive MIMO System With Power Control Methods

no code implementations4 Oct 2021 Masaaki Ito, Issei Kanno, Takeo Ohseki, Kosuke Yamazaki, Yoji Kishi, Thomas Choi, Andreas F. Molisch

Cell-free massive multiple-input multiple-output (CF mMIMO) systems are expected to provide faster and more robust connections to user equipments (UEs) by cooperation of a massive number of distributed access points, and to be one of the key technologies for beyond 5G (B5G).

THz Band Channel Measurements and Statistical Modeling for Urban D2D Environments

no code implementations28 Sep 2021 Naveed A. Abbasi, Jorge Gomez-Ponce, Revanth Kondaveti, Shahid M. Shaikbepari, Shreyas Rao, Shadi Abu-Surra, Gary Xu, Charlie Zhang, Andreas F. Molisch

In this paper, we present a first extensive set of channel measurements for urban outdoor environments that are ultra-wideband (1 GHz 3dB bandwidth), and double-directional where both the transmitter and receiver are at the same height.

Uplink Energy Efficiency of Cell-Free Massive MIMO With Transmit Power Control in Measured Propagation Channels

no code implementations4 Aug 2021 Thomas Choi, Masaaki Ito, Issei Kanno, Takeo Oseki, Kosuke Yamazaki, Andreas F. Molisch

Therefore, if the "target" spectral efficiency (SE) is met, it is important to optimize the uplink EE when setting the transmit powers of the UEs.

Intelligent Surface Optimization in Terahertz under Two Manifestations of Molecular Re-radiation

no code implementations2 Jun 2021 Anish Pradhan, J. Kartheek Devineni, Harpreet S. Dhillon, Andreas F. Molisch

The operation of Terahertz (THz) communication can be significantly impacted by the interaction between the transmitted wave and the molecules in the atmosphere.

Using a Drone Sounder to Measure Channels for Cell-Free Massive MIMO Systems

2 code implementations23 May 2021 Thomas Choi, Jorge Gomez-Ponce, Colton Bullard, Issei Kanno, Masaaki Ito, Takeo Ohseki, Kosuke Yamazaki, Andreas F. Molisch

Measurements of the propagation channel form the basis of all realistic system performance evaluations, as foundation of statistical channel models or to verify ray tracing.

Air-to-Ground Directional Channel Sounder With 64-antenna Dual-polarized Cylindrical Array

2 code implementations13 Feb 2021 Jorge Gomez Ponce, Thomas Choi, Naveed A. Abbasi, Aldo Adame, Alexander Alvarado, Colton Bullard, Ruiyi Shen, Fred Daneshgaran, Harpreet S. Dhillon, Andreas F. Molisch

Unmanned Aerial Vehicles (UAVs), popularly called drones, are an important part of future wireless communications, either as user equipment that needs communication with a ground station, or as base station in a 3D network.

Co-Located vs Distributed vs Semi-Distributed MIMO: Measurement-Based Evaluation

no code implementations29 Sep 2020 Thomas Choi, Peng Luo, Akshay Ramesh, Andreas F. Molisch

With the growing interest in cell-free massive multiple-input multiple-output (MIMO) systems, the benefits of single-antenna access points (APs) versus multi-antenna APs must be analyzed in order to optimize deployment.

Favorable Propagation with User Cluster Sharing

no code implementations25 Jun 2020 Chelsea Miller, Peter J. Smith, Pawel A. Dmochowski, Harsh Tataria, Andreas F. Molisch

We use these results to examine the detrimental effects of user cluster sharing on FP behavior, and demonstrate the superior performance of the ULA as compared to the UCA and the HURA with equal inter-element spacing.

Hybrid Beamforming Structure for Massive MIMO System: Full-connection v.s. Partial-connection

no code implementations18 Jun 2020 Zheda Li, Shengqian Han, Andreas F. Molisch

In this article we compare the performance of two typical hyrbid beamforming structures for multiuser massive MIMO systems, i. e., the full- and partial-connection structures.

Standardization of Propagation Models: 800 MHz to 100 GHz -- A Historical Perspective

no code implementations15 Jun 2020 Harsh Tataria, Katsuyuki Haneda, Andreas F. Molisch, Mansoor Shafi, Fredrik Tufvesson

This motivated the development of the first standardized propagation model by the European Cooperation in Science and Technology (COST) 207 working group.

Impact of UAV Wobbling on the Air-to-Ground Wireless Channel

1 code implementation6 Apr 2020 Morteza Banagar, Harpreet S. Dhillon, Andreas F. Molisch

This paper studies the impact of unmanned aerial vehicle (UAV) wobbling on the coherence time of the wireless channel between UAVs and a ground user equipment (UE), using a Rician multi-path channel model.

Information Theory Signal Processing Information Theory

Experimental Investigation of Frequency Domain Channel Extrapolation in Massive MIMO Systems for Zero-Feedback FDD

no code implementations24 Mar 2020 Thomas Choi, François Rottenberg, Jorge Gomez-Ponce, Akshay Ramesh, Peng Luo, Jianzhong Zhang, Andreas F. Molisch

Estimating downlink (DL) channel state information (CSI) in frequency division duplex (FDD) massive multi-input multi-output (MIMO) systems generally requires downlink pilots and feedback overheads.

A Machine Learning Solution for Beam Tracking in mmWave Systems

no code implementations29 Dec 2019 Daoud Burghal, Naveed A. Abbasi, Andreas F. Molisch

Utilizing millimeter-wave (mmWave) frequencies for wireless communication in \emph{mobile} systems is challenging since it requires continuous tracking of the beam direction.

BIG-bench Machine Learning

Supervised ML Solution for Band Assignment in Dual-Band Systems with Omnidirectional and Directional Antennas

no code implementations28 Feb 2019 Daoud Burghal, Rui Wang, Abdullah Alghafis, Andreas F. Molisch

This paper considers the band assignment (BA) problem in dual-band systems, where the basestation (BS) chooses one of the two available frequency bands (centimeter-wave and millimeter-wave bands) to communicate with the user equipment (UE).

Binary Classification

Exploiting Wireless Channel State Information Structures Beyond Linear Correlations: A Deep Learning Approach

no code implementations3 Dec 2018 Zhiyuan Jiang, Sheng Chen, Andreas F. Molisch, Rath Vannithamby, Sheng Zhou, Zhisheng Niu

Knowledge of information about the propagation channel in which a wireless system operates enables better, more efficient approaches for signal transmissions.

Dimensionality Reduction

Band Assignment in Dual Band Systems: A Learning-based Approach

no code implementations2 Oct 2018 Daoud Burghal, Rui Wang, Andreas F. Molisch

In this work, we use a machine learning framework to provide an efficient and practical solution to the band assignment problem.

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